If the second fob doesn't work and the first fob won't work either and these batteries work fine elsewhere, then that leaves only one thing. It's an issue with the car and not the fobs or batteries.

 

Does the car start with the fob and it's just the remote functions that don't work or is it a total inability to communicate?

 

I have this EXACT problem and I thought I was going nuts. I tried replacing the Panasonic CR2025 with an Energizer one but it doesn't work at first. The remote lights up on button press but the car doesn't respond. I switched to another unbranded CR2025 and worse still, the remote doesn't even light up.

I swapped a Panasonic battery from my secondary fob into my primary one and it immediately worked. I put the Energizer into my secondary fob and it stopped working as expected.

I've tested both the new batteries with a multimeter and they are reading above 3.3v whereas the secondary Panasonic was reading approximately 3v.

Eventually, I got the Energizer to work by going really close to my car, like literally a foot away and spamming the fob buttons. It finally registered and then after that it worked normally.

Nothing makes sense. What gives???